Rum Caviar tutorial

A friend of mine made something a few months ago that blew my mind. It’s called Rum Caviar, and it’s barely sweetened rum in the form of little golden spheres, just like fish eggs:

They stay like that until you eat them, and then they melt deliciously in your mouth with all that rum flavor. Absolutely fantastic, and so fun!

I’ve been begging my friend ever since to make these again sometime so I could post the instructions here, and he finally got a chance to do it, so here you go! (Update: and go check out the site he just started, DareToDessert.com!)

Rum Caviar instructions

You’ll need:

Vegetable oil

Dark rum

Brown sugar

Agar-agar powder (which can be found in Asian markets, or the ethnic section of some grocery stores, or you can just buy it from Amazon)

Obviously, how much you need depends on how big a batch you want to make. This recipe is for two drinks’ worth of Rum Caviar and used: 3/4 cup dark rum, 2 grams agar-agar powder, 1/4 cup brown sugar and about 20 ounces of vegetable oil. For a bigger batch, he recommends buying: a 4 oz bag of agar-agar, a 750 ml bottle of dark rum,a bag or box of brown sugar and a 32 oz jug of vegetable oil – scale the ingredients to the batch size you want. Note that the vegetable oil can be re-used: just chill it in between batches, and filter it if it gets goopy. He also recommends using a kitchen scale with gram measurements to be sure you get the measurements just right.

Fill your tall, narrow glass with vegetable oil. The taller your glass is, the better it will work, because this is what the hot rum mixture needs to travel through to cool off and solidify. If the glass is too short, the spheres may join at the bottom and you’ll have one giant lump of rum jelly. Place the glass of oil in the freezer and chill for 30 minutes.

When 30 minutes is up, stir 3/4 cup dark rum and 2 grams agar-agar powder in a saucepan on high heat until it begins to boil. Quickly add 1/4 cup brown sugar, stir to dissolve sugar, bring back to a boil, and remove from heat. The sugar is important because it adds density to the rum and makes it sink in the oil. Without it, your rum would float at the top and make little half-spheres. Let the rum mixture sit for about 2 minutes and remove the vegetable oil from the freezer.

Suck up the rum mixture in an eye dropper and squeeze little drops of the mixture into the cold oil, making sure to keep your hand moving at all times to prevent one big ball from forming at the bottom (that is, don’t put every drop right into the middle of your oil’s surface). As the rum collects into spheres, it will become heavy and drop through the oil, cool off, and lay waiting for you to scoop it up from the bottom. Work quickly because the rum will solidify in the saucepan. If this does happen, you can melt it again on low heat, being sure to stir constantly, and continue the spherification process.

Once you’re finished, either scoop the balls out with a small slotted spoon or pour through a mesh sieve or cheesecloth to collect the spheres from the oil. Drop them in cold water for a few seconds to wash the oil off and you’re ready to go.

Optional: if you’re making a lot of this and don’t want to go to the hassle of making little balls, you can just let the mixture cool and solidify in the sauce pan, then put it through a food processor. It comes out looking like little shards of glass, which is also really cool-looking.

The flavor, and uses

Rum Caviar has a milder flavor than liquid rum and hardly any sweetness from the brown sugar. You can use this:

In cocktails that call for rum. Because the rum caviar has a little sugar and agar-agar weighing it down, and a little of the rum burns off in the cooking, use a 1.5 to 1 ratio. That is, if a cocktail calls for 1 ounce of rum, try 1 1/2 ounces of rum caviar.

As a drink itself – it’s a wonderful treat all by itself, served with a spoon.

Put it over ice cream and bananas.

As a way to serve eggnog to drinking and non-drinking guests, a problem for many hosts and hostesses around the holidays – just make a batch of no-alcohol eggnog, and spoon in some of the Rum Caviar for your drinking guests. People will still be talking about it next year!

Served in a bowl with a spoon. Served this way, it captures the feel of caviar – or dessert. If you like the pictured bowl, you can buy it here.

Storage

How to store: in an airtight container, in the fridge, with a few tablespoons of water at the bottom.

How long they’ll keep: we estimate at least several weeks, based on the ingredients and their shelf life, but have not tested this (both times he made them, they got consumed within 72 hours).

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Comments

It does, but this is minimized by removing it from heat as soon as it starts to boil. You could add the brown sugar and agar powder at the same time and once it comes to a boil remove it from heat immediately. That’s part of the reason the resulting spheres are at a ratio of 1.5 to 1 compared to the actual rum.

Hello! I just want to ask if it’s possible to just use iced water instead of oil? And have you tried other alcoholic drinks? I have a bottle of umeshu but wanted to ask for your opinions first. Thanks!

I haven’t tried the ice water over oil but my assumption would be that the drops would sink too quickly. The oil is really thick and helps to slow the little guys down as they drop to the bottom of the glass. If you do happen to try it, I’d love to hear how it worked out. As for other alcohols, I’ve had success with port wine and since Umeshu is a similarly dark and sweet wine I’d say it should work. It’s already pretty thick and high in sugar so you don’t have to add any sugar to it, just the agar agar powder. I would recommend trying a small batch first, though, before potentially wasting your whole bottle.

Short answer: no, that wouldn’t work. Long answer: The rum is oliophobic, not hydrophobic, so you’d end up with sugary rum-water. Also, the added density of the oil helps keep the pellets together. He this helps!

I’ve been searching for about 30 minutes now. Do you think you could provide a picture of what the agar agar/rum/gelatin looks like if it’s been food-processed instead of dripped? The shards sounds interesting but I’d like to see it before I try it.

We didn’t do that with the batch we photographed (obviously, as you see from the photos, LOL). Honestly, the caviar balls look cooler, but the shards are a neat option when you don’t have time to make a huge batch of the caviar.

The article says 2 grams agar-agar for 3/4 cup of rum (approx 177 ml), and 4 oz agar-agar for 750 ml of rum – but there are 28 grams/oz, so it calls for 56 times more agar-agar for 4.2x more rum – which measurement is wrong?

Take the original recipe of 3/4 cup rum and 2 grams agar agar and multiply that by the number of batches you’d like to make. So a 750 ml bottle of rum will give you about 4 batches, which would need 8 grams agar agar powder.Most suppliers sell agar agar in bags only as small as 4 oz, so really the suggestion was just that you purchase a bottle of rum and a bag of agar agar and then use the recipe for your measurements. You’ll also have a little bit of rum left in the bottle after those 4 batches.

yes. i tried making a batch with the larger measurements, and pretty much wasted about $25 worth of ingredients. it still tastes ok, i suppose, but came out way too thick. instead of forming little caviar balls, it came out more like worms. i kinda covered by referring tot hem as ‘rummy worms’, but still it was a disaster.

This is fascinating. I think I will have to try it. In short, you must use a high sugar alcohol. Dark rum: yes, Brandy: yes, etc. Agar, which is seaweed, forms a webbed network full of pores with the sugar in solution. THink of it as a ball of nets. Ethanol molecules are trapped within this web. Agar is used often in molecular biology labs for DNA testing via gel electrophoresis. In molecular biology, the denser the agar network, the smaller the molecule must be to pass through it. This recipe must make a dense ball to trap ethanol – its only C2H6O!!

We just tried it following the instructions, and while they formed discreet balls of rum while sinking, they all just coalesced into one amorphous blob in the bottom of the glass. Darn! We were using overproof dark rum, and we even tried adding more agar and re-boiling, then letting it cool down to about room temperature before dropping it into the oil. Still no luck. Any thoughts about the alcohol content affecting the process, or any other ideas what we should try?

Were you careful to keep your hand moving as you dropped them into the oil, so they weren’t all falling down the same tunnel, so to speak? Offhand, that’s the one thing I know of that will cause what happened there.

So sorry to hear that! I’ve made the caviar with 2 different kinds of dark rum: Bacardi and Brugal (Brugal is a dark, really strong Dominican rum). Sometimes even the slightest discrepencies will cause the process to fail. Try keeping the oil in the freezer for an extra fifteen minutes and see if that helps to slow them down as they drop to the bottom. You could also add a bit more sugar. I hope it works!

Hrm. I wonder if molasses would work in place of the brown sugar. It’d give a little bit stronger flavor, potentially, but should match well with the rum. Also, as a (very viscous) liquid, it wouldn’t need as long as melt/dissolve as the brown sugar, so you’d lose less alcohol from the boiling.

1. Rum with 80% Alcohol does *not* work (the Agar-Agar builds clumps with it, right after throwing it in. 2. You do not need the sugar. The drops sank just fine (and slower) in my oil without sugar. I used sunflower oil. Some drops stay at the top initially, due to surface energy, but they start to fall sooner or later. If not they are easy to push down. 3. All alcohols around 40% I tried did work (Vodka, Cointreau, Rum 53%) 4. I used twice the amount of Agar-Agar. My package said to cook it at least for 2 minutes, and I never was successful when I didn’t cook it that long. Unfortunately, then almost all the alcohol is gone! 5. Therefore I advise the following: 5.1. Heat 50ml of water and 6g Agar Agar in the smallest pot you can find, depending on your pot you might need more water. Cook for the amount of time the Agar-Agar package requires. 5.2 The substance should be slightly “slimy”. Now add 100ml of alcohol (e.g. 100ml Cointreau) and cook *very shortly* (just for mixing it in). 5.3 Fill the liquid into your drop-thingy 5.4 Wait and cool. I cooled my liquid under cold water. It definitely shouldn’t be hot, and mine wasn’t even warm any more. Your best indicator is the texture of the substance. It should still be able to flow around and form drops. 5.5. Start slowly, with one single drop. Put it gently without much falling distance onto the oil. It will swim at the top, leave it there for a while. If it doesn’t fall by itself after 10 seconds or so, force it down. 5.6. After your first drop(s) reached the bottom, *watch* them. If they move, they should roll around. If they get flatter and flatter and finally burst, you still have to wait some time. Repeat trying single drops until they don’t burst any more. 5.7. Now you can start to slowly put more drops in. With time you can go faster and faster, I suggest a round motion to put “spirals” of drops into the oil. If the texture is right, you can go very fast. I accidentally created drops of 1cm in this phase and it stayed in shape just fine.

Long answer: I didn’t try rum, but I thought that all of these drinks with approximately the same amount of alcohol should have about the same density. I googled this now and found [1] and [2]. According to the tables there, all typical kinds of alcohol should work with all typical kinds of cooking oil. The only overlap is when you use very heavy kinds of oil and very light kinds of Vodka. But even then, according to [1] the lightest Vodka is around 0,95 and according to [2] the heaviest cooking oil isn’t heavier than 0,93. So still, the oil should “swim” on top of the Vodka, i.e., the Vodka should sink in the oil. The given oil densities are valid for about room temperature. At around 0 °C, the density of oil will be higher I guess, but I don’t think the effect will be large (maybe 0,92 to 0,921 or something). Unfortunately I couldn’t find any references.

From a physics standpoint, it should therefore work for all listed alcohols without sugar. It can however be hard to break the surface energy, maybe you experienced that?

In addition, I don’t know how the agar agar affects the density of the alcohol. But judging from the other alcohols, the effect shouldn’t be high.

I just wanted to clarify something about end use. When you use the rum caviar for mixing drinks, how well does the rum diffuse into the drinks – are people eating the balls as they drink their eggnog, or do the balls dissolve and infuse the drink with rum? If they dissolve, how does the agar-agar affect the consistency of the beverage?

If I serve them on top of a dessert (made of custard or whipping cream – something moist), will this not cause the caviar to dissolve? Really want to try making this but thought I should check about this first before I go to the hassle of trying to find agar agar powder or an appropriate eye dropper.

I have a fun trick. Might be great with this ! I have a soda siphon. It takes a soda “charger”. I have used it many times for whipped cream, by using a whipped cream “charger”. I made a mistake once, and put in cream and a SODA charger. Bam ! “Fuzzy Whipped Cream” as I called it ! I have done this a million times since, and always has a surprise for my guests ! A squirt into a nice wine class, and a scoop of this “caviar” on top??? Would be awesome. By the way. I do not recommend the fuzzy whipped cream for kids under say, 10. Don’t think it is good for them is all. Enjoy !